The Japanese carrier, which currently is mainly Android and iOS, has backed HTML5 development

KDDI, which runs one of Japan's largest mobile networks, is considering selling smartphones based on the new Firefox operating system from Mozilla.

Company president Takashi Tanaka has indicated that KDDI is examining various options related to the fledgling OS, including sales, according to spokesman Takeshi Ota.

Mozilla has promised to develop Firefox OS on standard Internet technologies such as HTML5 and JavaScript, including core functionality such as the dialer and address book. This should mean that phones running the software require lower specifications and can be sold more cheaply.

KDDI has supported technologies such as HTML5. Earlier this week Tanaka made a surprise appearance at a study group for the technology. The operator currently offers mainly iPhones and smartphones that run Android, as well as an older Toshiba handset that runs an older version of the Windows Phone OS.

The use of open technologies should also make the software of the phones highly configurable, allowing operators to customize the look of their devices and offer their own app stores. While all three main Japanese carriers sell handsets branded with their own names, KDDI has launched a whole line of phones based on its own design, the "Infobar" series.

KDDI was slow to embrace the smartphone trend, and lost users to local rivals such as Softbank as a result. But the company has turned around its fortunes since it began offering Apple's iPhone in 2011.

On Tuesday, Mozilla introduced a Firefox OS preview phone for developers that will go on sale soon online. The official release of the OS isn't expected until later this year.

The first phones based on Firefox OS are expected to go on sale in Brazil when the OS is released, and operators in other regions, including TelefA3nica Digital, Deutsche Telekom, and U.S. operator Sprint have said they will support the program. Japanese carrier Softbank has agreed to acquire Sprint in a US$20 billion deal.